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Status and needs of Sea level Observing Systems in East and

South East Asia

GCOS Regional Meeting for East and South East Asia, Singapore , 16-18 September 2002

John Church, CSIRO Australia [email protected]

Philip Woodworth, POL (GLOSS Chairman) [email protected]

Thorkild Aarup, GLOSS Technical Secretary IOC [email protected]

C.K. Shum, Ohio State Univ. (GLOSS Asia-Pacific Regional Contact) [email protected]

Contents of Presentation:

1. Rationale - Why monitor sea level changes and how?

2. The GLOSS programme

3. Status of sea level data availability from the Region

4. Recommendations

mailto:[email protected]
















Why Measure Sea Level Changes?

Maldives Int. Airport

Different Time-Scales

• Rapid changes due to tsunamis

• Daily changes due to tides and surges

• Seasonal changes

• Interannual changes e.g. due to ENSO

• Long term changes due to climate change

Causes of Sea Level Change

• Local processes in river/coastal regimes

• Ocean circulation changes

• Regional and global climate changes

• Geological processes

•Coastal management requires understanding of past and future changes in sea level and related ocean conditions

• Practical applications – e.g. to predict flood risks, coastal

navigation etc.


Sea level has risen by about 120 m since the last glacial

maximum


Over several hundred years there has been an increase in the rate of sea-level

rise.

• Most records show evidence

for

rising sea levels during the

past

century

• IPCC concluded that there

has

been a global rise of

approximately 10-20 cm

during the past 100 yearshttp://www.pol.ac.uk/psmsl/programmes/

gloss.info.html

Changes in Sea Level during the 20th century


Some E and SE Asia Long Records

Example records from India, Malaysia, Singapore, Thailand, Vietnam, Hong Kong, South Korea, Russia, Japan and Philippines.

Sea level rise during the 20Sea level rise during the 20thth century has had regional impacts. century has had regional impacts.Marsh Destruction at Blackwater, Maryland, Due to Sea Level RiseMarsh Destruction at Blackwater, Maryland, Due to Sea Level Rise

Leatherman, 2001

“sea level is projected to rise by 0.09 to 0.88 m between 1990 and 2100”

about 2 to 4 times the rate for the past 100 years

Thermal expansion 0.11 to 0.43 mGlaciers and ice caps 0.01 to 0.23 mGreenland -0.02 to 0.09 mAntarctica -0.17 to 0.02 m

For the IS92a greenhouse gas scenario

A reduction in the return period of extreme events.

Return period of surge heights at Immingham (UK)

Longer Term Projections

• Continued glacier melting• East Antarctic Ice Sheet • West Antarctic Ice Sheet

opinion not favouring catastrophic collapse

• Continued thermal expansion for centuries• Greenland melting

greater than +3C then continued melting+5C - 3m over 1000 years

Projected Coastal Megacities: 2010 By 2100, the number of people who will have to respond to coastal flooding will be tens

of millions/year; Most vulnerable regions are South and South-East Asia; Africa; Carribean; Indian Ocean Islands; Pacific Ocean Islands.

Istanbul

LagosLima

Buenos Aires Rio de JaneiroMadras

KarachiJakarta

Calcutta

Bombay

Bangkok

Manila

Shanghai

Osaka

Tokyo

Seoul

Tianjin

Dhaka

New York

Los Angeles


Measuring Sea Level Changes

Tide Gauge (float)

Bottom Pressure Gauge

Altimeter System


Tide Gauges are still essential in the “Age of Altimetry”

Acoustic Gauge in Australia

• Principle of continuity, relative low cost of gauges

• Long records for secular trend/acceleration studies (e.g. for input to IPCC)

• Higher frequency sampling important

• High latitude regions of ice coverage

• Altimeter calibrations (‘absolute’ and ‘relative’)

• Coastal applications (GOOS Coastal Module)

•Vertical land motion (using GPS)


GLOSS - The Global Sea Level Observing System

•For many years agencies have sent data to the PSMSL.

GLOSS aims to ensure the provision of high quality sea-level

data for regional and global applications.

•Establishment of high quality regional and global sea level

networks for application to climate, oceanographic and coastal

sea-level issues

•Coordinated by the Intergovernmental Oceanographic

Commission (IOC) for the JCOMM of WMO/IOC

• Major contributor to IOC’s Global Ocean Observing System

(GOOS)


The GLOSS Programme

• GLOSS Core Network (GCN)

• Regional Densifications of the GCN

• Long Term Trends (LLT)

• Altimeter calibration (GLOSS-ALT set)

• Ocean Circulation (GLOSS-OC set) GLOSS Core Network (GCN) with approx. 280

stations

An effective regional and global system requires:

delayed mode original data (e.g. hourly values) be sent to one of the GLOSS International Archiving Centres (Most countries are now doing this but it remains a problem for a few (e.g. national security, or cost recovery)).

IAC’s are PSMSL, Univ. Hawaii and National Tidal Facility Australia.

fast sea level data to be sent from GLOSS Core Network sites to the GLOSS Fast Centre (University of

Hawaii Sea Level Center) within one week.


GCN Status E. and S.E. Asia

GCN Status Category:

Measured by PSMSL data receipts

•up-to-date

•a bit slow

•historical data only

•no data

Status of data submission(see http://www.pol.ac.uk/psmsl/reports.national+regional/)

India – no hourly data, national security issuesBangladesh – major investments needed in difficult estuary environmentMyanmar – first contact for many years made in 2002Thailand – MSL delivered promptly, but gauges need upgradingMalaysia – excellent tide gauge and GPS networksSingapore – excellent tide gauge and GPS networks

http://www.pol.ac.uk/psmsl/reports.national+regional/

Vietnam – new recent gauges for flood warning.PR China – MSL delivered regularly if a bit behind. More gauges are known to exist than provide data to international data banks.Hong Kong China – long standing data provision.Japan – excellent networks of several agencies.S. Korea – good gauges. MSL data behind.N. Korea – contacts lapsed.Russia – good formal contacts. Several gauges destroyed by tsunami. Need for modernisation.Philippines – long standing contacts lapsed.Indonesia – large gauge networks, none of which now work due to funding problems.

Major Issues for the Region

Comparatively few tide gauges in the region are equipped with GPS for monitoring vertical land movements (major exception of Japan), see http://www.soest.hawaii.edu/cgps_tg

Need for major investment in upgrade of tide gauges (e.g. for fast data provision as well as delayed-mode) and for GPS alongside the gauges. (No plans as yet for bids, e.g. to World Bank, for resources for the region, as for Africa.)

Historical data

GLOSS/IODE Data Archaeology Project

Agencies which have historical sea level data in non-computer form (e.g. on paper charts, or paper tape) are asked to inform IOC or PSMSL which may be able to arrange for computerisation of the information.


Ongoing Regional Activities

•Regional networks of gauges with greater spatial density, to serve the particular oceanographic interests of those regions - example: Asia-Pacific Space Geodynamics (APSG) activities

•Research in the measurement and characterization of Asia-Pacific regional and global sea-level rise

•Data center to be established, potentially at NTF, or other sites providing data products including sea-level measurements, wave heights, wind speed, and integrated water vapor from multiple satellites

• GLOSS contributes to the activities of national agencies by improving the standards for sea level recording around the world

•Annual training courses on the techniques of tide gauge operations, and workshops on special interests e.g. measurements in environmentally hostile areas. Next course Malaysia April 2003.

Recommendations

Establish a Regional Project, under the auspices of GLOSS, to further develop a networks of modern tide gauges and geodetic instrumentation to serve regional requirements.

Specific Recommendations

Employ a Regional Coordinator to pursue the Regional Project.

That historical data (hourly, delayed mode and fast data) be submitted to the GLOSS data archives (including if necessary, conversion to computer compatible form)

That tide gauge instrumentation at GLOSS sites be upgraded to allow efficient quality control and submission of delayed mode and fast data.

That a subset of gauge sites be equipped with Continuous GPS (CGPS) receivers and/or other geodetic devices, in order to monitor vertical land movement.

That tide gauges suitable for ongoing calibration of satellite altimeter missions (e.g. deep ocean islands) be included in international programs (GLOSS-ALT).

That the project also contribute to observations quantifying the causes of sea level change.

That programs be established to study the social, economic and environmental consequences of sea level change; including the impact and frequency of extreme events.


GLOSS Data Availability

Data from GLOSS tide gauges

• Permanent Service for Mean Sea Level http://www.pol.ac.uk/psmsl/

• University of Hawaii Sea Level Center http://www.soest.hawaii.edu/UHSLC/

• National Tidal Facility (Australia) Southern Ocean Centre http://www.ntf.flinders.edu.au

GLOSS sea level data and information on each gauge in the GLOSS Core Network are also available from PSMSL on CD-ROM.

Further Information GLOSS Technical Secretary Permanent Service for Mean Sea LevelIntergovernmental Oceanographic Proudman Oceanographic LaboratoryCommission (IOC), UNESCOemail: [email protected] email: [email protected]











http:// status and needs of sea level observing systems in east and south east asia gcos regional...

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